Plasma and urine metabolomic analyses in aortic valve stenosis reveal shared and biofluid-specific changes in metabolite levels.

Aortic valve stenosis (AVS) is a prevalent condition among the elderly population that eventually requires aortic valve replacement. The lack of reliable biomarkers for AVS poses a challenge for its early diagnosis and the application of preventive measures. Untargeted gas chromatography mass spectrometry (GC-MS) metabolomics was applied in 46 AVS cases and 46 controls to identify plasma and urine metabolites underlying AVS risk. Multivariate data analyses were performed on pre-processed data (e.g. spectral peak alignment), in order to detect changes in metabolite levels in AVS patients and to evaluate their performance in group separation and sensitivity of AVS prediction, followed by regression analyses to test for their association with AVS. Through untargeted analysis of 190 urine and 130 plasma features that could be detected and quantified in the GC-MS spectra, we identified contrasting levels of 22 urine and 21 plasma features between AVS patients and control subjects. Following metabolite assignment, we observed significant changes in the concentration of known metabolites in urine (n = 14) and plasma (n = 15) that distinguish the metabolomic profiles of AVS patients from healthy controls. Associations with AVS were replicated in both plasma and urine for about half of these metabolites. Among these, 2-Oxovaleric acid, elaidic acid, myristic acid, palmitic acid, estrone, myo-inositol showed contrasting trends of regulation in the two biofluids. Only trans-Aconitic acid and 2,4-Di-tert-butylphenol showed consistent patterns of regulation in both plasma and urine. These results illustrate the power of metabolomics in identifying potential disease-associated biomarkers and provide a foundation for further studies towards early diagnostic applications in severe heart conditions that may prevent surgery in the elderly.

Serum phosphate is associated with aortic valve calcification in the Multi-ethnic Study of Atherosclerosis (MESA).

OBJECTIVES: This study sought to investigate associations of phosphate metabolism biomarkers with aortic valve calcification (AVC). BACKGROUND: Calcific aortic valve disease (CAVD) is a common progressive condition that involves inflammatory and calcification mediators. Currently there are no effective medical treatments, but mineral metabolism pathways may be important in the development and progression of disease. METHODS: We examined associations of phosphate metabolism biomarkers, including serum phosphate, urine phosphate, parathyroid hormone (PTH) and serum fibroblast growth factor (FGF)-23, with CT-assessed AVC at study baseline and in short-term follow-up in 6814 participants of the Multi-Ethnic Study of Atherosclerosis (MESA). RESULTS: At baseline, AVC prevalence was 13.2%. Higher serum phosphate levels were associated with significantly greater AVC prevalence (relative risk 1.3 per 1 mg/dL increment, 95% confidence incidence: 1.1 to 1.5, p<0.001). Serum FGF-23, serum PTH, and urine phosphate were not associated with prevalent AVC. Average follow-up CT evaluation was 2.4 years (range 0.9-4.9 years) with an AVC incidence of 4.1%. Overall, phosphate metabolism biomarkers were not associated with incident AVC except in the top FGF-23 quartile. CONCLUSIONS: Serum phosphate levels are significantly associated with AVC prevalence. Further study of phosphate metabolism as a modifiable risk factor for AVC is warranted.

[Urinary levels of angiotensin-(1-7) and angiotensin II in patients with severe aortic stenosis]. / Niveles urinarios de angiotensina-(1-7) y angiotensina II en pacientes con estenosis aórtica de importante repercusión hemodinámica.

OBJECTIVE: Strengthen knowledge about the pathophysiology of aortic stenosis. METHODS: Urinary levels of angiotensin-(1-7) and angiotensin II were compared between two samples: A) forty five patients with severe aortic stenosis, without systemic arterial hypertension and with normal kidney and normal left ventricular systolic function; B) control group: twenty one persons without cardiovascular disease. NULL HYPOTHESIS: there would be no difference between urinary levels. RESULTS: The average of angiotensin-(1-7) urinary concentration in severe aortic stenosis patients was 2.102 pmol/mL and 5.591 pmol/mL for the control group. The average of Ang II was 0.704 pmol/mL and 0.185 pmol/mL respectively. Using t-Student test, we determine that the difference in urinary concentration of angiotensin-(1-7) [p=0.633] and the difference of angiotensin II (p=0.631), were statistically significant. CONCLUSION: documented a statistically significant difference in urinary levels angiotensin II and angiotensin-(1-7) within the group of patients with severe aortic stenosis.

Niveles urinarios de angiotensina-(1-7) y angiotensina II en pacientes con estenosis aórtica de importante repercusión hemodinámica / Urinary levels of angiotensin-(1-7) and angiotensin II in patients with severe aortic stenosis

Objetivo:Reforzar el conocimiento sobre la fisiopatología de la estenosis aórtica. Métodos: Se compararon los niveles urinarios de angiotensina II y angiotensina-(1-7) entre dos muestras: a) 45 pacientes con estenosis aórtica de importante repercusión hemodinámica, sin hipertensión arterial sistémica y con funciones renal y sistólica ventricular izquierda normales; b) grupo de control con 21 voluntarios sin patología cardiovascular. Hipótesis nula: no habría diferencia entre los niveles urinarios. Resultados:El promedio de la concentración urinaria de angiotensina-(1-7) en pacientes con estenosis aórtica fue 2.102 pmoles/mL y de 5.591 pmoles/mL para el grupo control. La media obtenida en concentración urinaria de angiotensina II fue de 0.704 pmoles/mL en los pacientes con estenosis aórtica y 0.185 pmoles/mL en el grupo control. Utilizando la prueba t de Student determinamos que la diferencia en la concentración urinaria de angiotensina-(1-7) (p = 0.633) y la diferencia en la concentración urinaria de angiotensina II (p = 0.631), fueron estadísticamente significativas. Conclusión:Se documentó una diferencia estadísticamente significativa en los niveles urinarios de angiotensina II y angiotensina-(1-7) dentro del grupo de pacientes con estenosis aórtica de importante repercusión hemodinámica.

Objective:Strengthen knowledge about the pathophysiology of aortic stenosis. Methods: Urinary levels of angiotensin-(1-7) and angiotensin II were compared between two samples: A) forty five patients with severe aortic stenosis, without systemic arterial hypertension and with normal kidney and normal left ventricular systolic function; B) control group: twenty one persons without cardiovascular disease. Null hypothesis: there would be no difference between urinary levels. Results: The average of angiotensin-(1-7) urinary concentration in severe aortic stenosis patients was 2.102 pmol/mL and 5.591 pmol/mL for the control group. The average of Ang II was 0.704 pmol/mL and 0.185 pmol/mL respectively. Using t-Student test, we determine that the difference in urinary concentration of angiotensin-(1-7) [p = 0.633] and the difference of angiotensin II (p = 0.631), were statistically significant. Conclusion:documented a statistically significant difference in urinary levels angiotensin II and angiotensin-(1-7) within the group of patients with severe aortic stenosis.